Alpha decay law of excited nuclei and its role in stellar decay rates

Abstract

$\alpha$ decay is one of the prominent decay modes in the nucleosynthesis of heavy and super-heavy elements synthesized at temperatures of the order of Giga Kelvin. To facilitate the investigation of the role played by the $\alpha$ decay half-lives of thermally excited nuclei in nucleosynthesis calculations, an empirical formula based on a model for the $\alpha$ decay of nuclei in their ground and excited states to daughter nuclei in their ground or excited states is presented. Constants appearing in the analytical expression for the $\alpha$ decay half-life obtained within the model are treated as adjustable parameters and fitted to experimental data on 342 $\alpha$ decays in the range of 82 $\le Z_p\le$ 94, to obtain an excitation energy-dependent decay law. Under the assumption that thermal equilibrium has been reached between nuclear states, temperature ($T$)-dependent half-lives, $t_{1/2}(T)$, for several of the experimentally studied $\alpha$ emitters with 65 $\le Z_p\le$ 94 are presented using available data on the half-lives of excited nuclei. Though the general trend is a decrease in $t_{1/2}(T)$ at elevated temperatures, exceptional cases with increased half-lives are found in the case of some isomeric states. A list of such isomers provided in this work motivates future work involving considerations of their thermal equilibration and role in shaping kilonova light curves.

arXiv comment13 pages, 8 figures

References in corpus (25)

• Nuclear ground-state masses and deformations: FRDM(2012)
• Kilonovae
• Universal decay law in charged-particle emission and exotic cluster radioactivity
• Radioactivity and thermalization in the ejecta of compact object mergers and their impact on kilonova light curves
• On the nuclear robustness of the r process in neutron-star mergers
• Universal decay rule for reduced widths
• Effects of formation properties in one-proton radioactivity
• The production of proton-rich isotopes beyond iron: The $\gamma$ process in stars
• Have Superheavy Elements been Produced in Nature?
• $\beta$-delayed fission in $r$-process nucleosynthesis
• Astromers: Nuclear Isomers in Astrophysics
• On the Validity of the Geiger-Nuttall Alpha-Decay Law and its Microscopic Basis
• Nucleosynthesis and observation of the heaviest elements
• Astromers in the radioactive decay of r-process nuclei
• Reanalysis of the (J = 5) state at 592 keV in 180Ta and its role in the neutrino-process nucleosynthesis of 180Ta in supernovae
• The $\gamma$-process nucleosynthesis in core-collapse supernovae. I. A novel analysis of $\gamma$-process yields in massive stars
• The p-process in exploding rotating massive stars
• Treatment of isomers in nucleosynthesis codes
• The impact of isomers on a kilonova associated with neutron star mergers
• Properties of the 5- state at 839 keV in 176Lu and the s-process branching at A = 176
• Superheavy Elements in Kilonovae
• Production of $p$-nuclei from $r$-process seeds: the $\nu r$-process
• Isochronic evolution and the radioactive decay of r-process nuclei
• Alpha decay of thermally excited nuclei
• Temperature dependence of cluster decay

Cited by in corpus (1)

• Impact of microscopic structural transitions on particle stability and lifetimes of hot nuclei